Some of the servicemen hurt/killed in Yemen during the special forces raid were heroically wounded by their own airplane, a CV-22 Osprey.[fox]
CV-22 Flying Death Trap
The Osprey is one of those brain-damaged ideas that the pentagon spends a gigantic amount of money on, then cannot back away from for fear of revealing its corruption and incompetence. It’s not a helicopter, it’s not an airplane, it’s a plane that can take off vertically then the engines rotate into forward-flight mode and it’s a propeller plane. With the forward-flight mode, it’s as fast as a regular propeller plane. It has three times the capacity of a UH-60 Blackhawk helicopter, and is about twice as fast. All that, for only 10 times the cost of a Blackhawk!
What if one engine fails on takeoff or landing?
Pity the poor Blackhawks: they have a market image problem thanks to “Blackhawk Down” (to be fair: most helicopters fly badly after they have been hit in the engine with an anti-armor rocket-propelled bomb) It’s the “hit in the engine” point that makes it interesting: helicopters have a nice stable profile when their engine (there’s just one, after all) fails: they fall out of the sky. There’s a trick called “autorotation” in which the pilot feathers the blades so they retain energy for a flare maneuver on landing and the helicopter lands well, if the pilot is skilled. [1] If something happens suddenly to one of the engines of an Osprey what does physics tell you is going to occur? Well, if it’s in forward-flight mode, you’ve got a glide landing. If you’re taking off or landing in vertical flight mode, things get very bad, very fast. Of course taking off and landing is when any aircraft is most vulnerable to ground fire; this is what makes the Osprey such a fantastic idea for troop transport.
Ospreys have had a history of problems besides being incredibly expensive. In order to keep the aircraft program viable, there have been a litany of fixes and the usual heavy propaganda on both ‘sides’ of the debate. But there are some data-points and the “hard landing” in Yemen was so “hard” that the aircraft was not flyable afterward and had to be destroyed by the special forces as they left the area.
The U.S. Central Command said in a statement Sunday that another service member was injured in a “hard landing” in a nearby location. An MV-22 Osprey aircraft used in the raid was unable to fly afterward and “was then intentionally destroyed in place.”[2]
It’s hard to sort out the account, variously there were 3 injured one of which was killed and at least one injury is attributed to the “hard landing.” [I will amend this posting if more facts become available]
Source: Texas Observer
Articles about the Osprey make it hard to tell how bad it is. For example, an article by Popular Mechanics triumphantly declares that “The Osprey a capable aircraft that has had only one fatal crash in combat.” Well, it may be capable, but it’s odd that Popular Mechanics doesn’t mention the non-combat crashes that have killed and injured passengers.
The V-22 Osprey had 8 hull-loss accidents with a total of 36 fatalities. During testing from 1991 to 2000 there were four crashes resulting in 30 fatalities. Since becoming operational in 2007, the V-22 has had four crashes including one combat-zone crash, and several other accidents and incidents that resulted in nine fatalities. [wikipedia]
One begins to appreciate the courage and heroism of the soldiers who get into one of the damn things. But I suppose they don’t have a choice.
The Osprey, however, brought me one of the best pieces of critical snark I have ever read. It’s a quote from Chuck Spinney, one of the brains behind the military reform movement of the 80s, and the F-16 fighter – a person who is intimately familiar with the many failures of the procurement system. Spinney wrote a piece entitled “Buy Before You Fly and the Politics of Risk Reduction”[3] in which he laid out a number of the problems with the Osprey program – including detailed references to minor failures and problems that could result in crashes or injuries. It’s devastating.
After Spinney’s article there was apparently a “secret” rebuttal being ushered around the halls of the pentagon. Spinney wrote a scathing response to the rebuttal[4] including some commentary on the aircraft proponents’ inability to decide whether the Osprey is a “helicopter” or an “airplane”. The rebuttal (not Spinney’s counter-battery) says:
However, to set the record straight, the autorotation issue is a common misconception with this aircraft. The V-22 is NOT a helicopter. It does not autorotate like a helicopter. It does, however, have approved emergency procedures that will allow the aircrew to safely land the aircraft when necessary. One of those procedures requires an autorotative-like state that requires a landing with higher rates of descent than a helicopter (initially), and a faster landing speed than a light, single engine helicopter might expect. The V-22 pilot is trained to set up for airplane mode flight and possible airplane mode glide rather than accept a potential for autorotation. But, should a V-22 ever need to autorotate, procedures are provided and the aircraft’s many crashworthiness features will come into play to maximize potential for occupant survivability at landing. These features include crash load attenuation in the stroking pilot, crew and passenger seats; self-sealing fuel cells and fuel lines with self-sealing breakaway valves; crash energy absorbing landing gear; and wing structure that will break away from the fuselage upon impact to reduce potential to collapse or otherwise threaten the cabin. Once again, this would be a Tilt Rotor autorotation – not a helicopter autorotation.
My head nearly exploded when I read “autorotative-like state” but we’re watching people gamble with others’ lives to protect their cash-cow. And did you catch the bit about the “crash load attenuation in the stroking pilot, crew and passenger seats” – in other words they know the thing lands so hard that they had to make seats on pistoned shock absorbers to keep the passengers and crew from breaking their necks. This is sold as “crashworthiness” and “survivability” but Spinney knocks the ball out of the park with his return volley:
Note that the anonymous authors claim the V-22 is not a helicopter, but that pilots are trained to set up for “airplane mode glide.” This rather confusing phraseology seems to imply it can glide like an airplane. Most people would not think of the Boeing 707 as being a good glider, and it has a glide ratio of 15, a glide slope of 3 degrees, and a rate of descent of 1,200 feet per minute. The V-22 in the airplane mode, on the other hand, has a glide ratio of 4.6, a glide slope of 12 degrees, and a rate of descent of about 3,500 feet per minute – so relative to a 707, it glides like a brick and is therefore is not a very good airplane either.
If you want an introduction to the V-22 story, the Texas Observer article is a good read.
At least Canada hasn’t been suckered into buying it.
I was fortunate(?) to see a pair of V-22’s depart from Hilo airfield the last time I was there. Quite a spectacle, especially the noise. F(*&#@g loud! We were in downtown so didn’t see the take-off, but did see them go through “rotate the engines to point forward” transition.
I recall wondering how the thing lands if the engine rotation device fails? The diameter of the rotors is so large that they cannot land with the engines in forward flight position…
Pedantic point: many helicopters are multi-engine, the Blackhawk has 2.
Shiv@#1:
At least Canada hasn’t been suckered into buying it.
I don’t think anyone else is that stupid.
I should probably do an article about the particular bit of inter-service braindamage that causes these VTOL aircraft to keep cropping up.
Sunday Afternoon@#2:
Quite a spectacle, especially the noise. F(*&#@g loud!
Yes, that’s so the special forces operators can insert stealthily.
Joking aside, you can’t even hear a blackhawk next to one of those things.
And, keep your distance! They’re not safe for onlookers, either.
I recall wondering how the thing lands if the engine rotation device fails? The diameter of the rotors is so large that they cannot land with the engines in forward flight position…
Then they just “glide” in and damn the rotors. I get the impression that a lot of flying a V-22 is choices between “lesser of two evils”
edantic point: many helicopters are multi-engine, the Blackhawk has 2.
True. You’re correct. I shouldn’t have said “engines” but rather “rotors” – the problem isn’t if the engine goes bad, it’s if the lift fails (which can be caused by either engine failing) Some poor bastards were flying an Osprey to England and one of the engines started having compressor stalls; that must have been nerve-wracking. “Iceland ho!” It isn’t a great glider but it can fly fine with just one engine if it’s in forward-flight mode.
Single engine failures in twin engine aircraft require prompt action by the pilot to avoid entering a spin especially if the angle of attack is large. Having the engines at the wing tips maximizes the moment about the yaw (vertical) axis when an engine fails. Having the mass of the engines out at the wing tips also maximizes the polar moment of inertia which will flatten the spin and make recovery more difficult if not impossible.
For context a glide ratio of 4.6 is about the same as that of a 15 meter glider with the landing gear down, full flaps and spoilers full deployed. It is a little better than the glide ratio of an F104 (the “missile with a man in it”).
militantagnostic@#5:
Sounds like Spinney’s right “it’s not much of an airplane, either”
Japan is going to buy Ospreys. The plan is for 17, but so far only 5 have been budgeted for.
Israel was going to buy them, but it seems someone chickened out, as they let their Letter of Agreement to buy 6 lapse.
timgueguen@#7:
Israel was going to buy them, but it seems someone chickened out, as they let their Letter of Agreement to buy 6 lapse.
That’s so weird – because usually when Israel buys a weapons system from the US, Congress gives Israel the money for it, and earmarks it. That’s why Israel is “buying” a few F-35s – because the US taxpayers are paying for them. Maybe Ospreys are so bad that the IDF doesn’t want to see any of its troops mangled.
As far as Japan: they’re on a pretty short leash, I suspect they buy what they’re told to buy.
Standard aviation joke: any landing you walk away from is a good one. Any landing you walk away from and the aircraft will fly again is a great one.
sonofrojblake@#9:
Any landing you walk away from and the aircraft will fly again is a great one.
There was some other piece by Spinney (that I can’t locate) where he points out that “pad the passenger” rather than “fix the plane” is a typical WWII-era soviet solution, and it’s nice to see that the pentagon is doing proper engineering.
Any story in which Dick Cheney is the good guy is pretty screwed up.
#10 Marcus Ranum
“pad the passenger” rather than “fix the plane” is a typical WWII-era soviet solution
Well the USSR did win the war in Europe. We helped.
Apparently the T-34 tank and the Petlyakov Pe-2 and Yakovlev Yaks worked. Admittedly the T-34 was poorly designed for humans. Or designed as best as one could in the USSR 1930s. But then, I am not sure that Stalin really cared about people
No idea about the aircraft.
jrkrideau
There was a later Soviet tank, the designation of which escapes me at the moment, that had an automatic gun loader which often tried to load the gunners arm.
Some of the servicemenOr you mean some of the terrorists attacking Yemen?
# 13 AndrewD
Does not surprise me. It is always too easy to over-engineer.
AndrewD @13
I remember having heard some comments about the unsafeness of the autoloader of T-72. Finnish Defence Forces used to have T-55s and T-72s before getting Leopard 2s.
jrkrideau @ #15:
It is always too easy to over-engineer.
True, but there are at least two very different ways to over-engineer: Americans would make it too complex, Soviets would make it too sturdy and too powerful (but perhaps too simple).
Gah… so much of what’s been said here is at least wrongly applied if not completely wrong.
Let me state that I’m not necessarily a fan of some of these things. I worry that the F-35, for instance, may indeed prove to be a turkey. Possibly for more reasons then you’re aware of, at least for more reasons then you’ve specified. And I know about the Osprey’s history of killing its crews during the development period. Unlike you, however, I appear to know a bit more about what caused those crashes. It looks like you went shopping for an Osprey critic and latched on to the first one you found.
I don’t think you chose very wisely. Where you think he knocked the ball out of the park, what he really did was kill his credibility. When talking about the glide ratio of a vehicle designed to replace helicopters, he compares it to what? A 707? A freaking airliner? Maybe this alleged expert wouldn’t expect an aircraft designed for efficient long distance flight to also be an efficient glider, but I would. It’s what makes them efficient.
Is 4.6 really so terrible? Guess what the glide ratio of the Space Shuttle was? About 4.5, at best. And it performed a power-off landing every time. With perhaps one failure, if you count re-entry as part of the landing phase. But I’d hope we can agree that that had nothing to do with the glide ratio.
In case anyone is wondering, other helicopters don’t achieve much better. Around 4.5 is the estimate I keep finding for the best an autorotating helicopter can achieve.
What, really, has glide ratio got to do with anything? It means how far you can go before you reach the ground. That’s it. If the Osprey in question had a better glide ratio it could have traveled a bit farther before it had to crash land. Do you honestly believe that the glide ratio of the best gliders in the world would have allowed the Osprey to return to friendly territory after the raid? Given that it was probably flying at low altitude it was bound to go down somewhere inside Yemen. At best, a better glide ratio would give the pilot a better choice of crash landing sites. I’m not saying that’s a bad thing, but it’s not really as critical as is being implied here. I mean it’s hardly a space shuttle, I don’t expect it will need a great deal of space to make a controlled, survivable crash landing.
On to the biggest problem in this post. On a photo of a crashing Osprey you pose what you assume is the damning question, “what if one engine fails on take-off or landing?”. The only thing that smug question does is expose your ignorance. Ignorance that you really, REALLY should have fixed before writing this article. Google makes it too easy, the only reason not to do the work is if you don’t want to know the answers. You want to know what it does? It continues under the power of its remaining engine, transmitted through a power shaft to the other side. Let me say that again with emphasis, BOTH ROTORS CONTINUE TO RECEIVE POWER. My guess is that a failure on takeoff would result in a need to abort the takeoff, it probably doesn’t have enough power to carry the weight of the full fuel tanks on a single engine. But the answer is the same for a Blackhawk, which as we’ve already established has two engines.
This answer applies to your response too, militantagnostic. Your analysis of the physics of an Osprey engine failure were based on assumptions of conventional aircraft. There is a shaft running through the wings connecting one side to the other. If one engine fails, the other takes over and supplies power to both rotors. Largely none of what you described would occur. To the pilot it would basically feel like his available power suddenly dropped substantially. In forward flight that’s not a big deal, it won’t be operating near full power.
So to connect all the dots together, plus add in a little of what I’ve found looking this subject up on my own, it seems that Ospreys cannot perform a vertical landing while autorotating, or at least they have difficulty achieving it safely. I don’t think the rotor system is heavy enough to carry enough potential energy to cushion a landing sufficiently. Research suggests it may be possible, but it’s borderline and may be difficult to achieve consistently. So they have to keep some forward velocity and using wing lift to help cushion the landing. Except they may still have those rotor blades available to provide a little extra lift at the end, enabling it to land at slower speeds then pure conventional flight would allow. Possibly a lot slower, if there’s nearly enough energy for a full vertical landing then a little extra wing lift could go a long way.
What does this have to do with current events in Yemen? Fuck all. The sum total of the arguments being presented here are “The Osprey can’t perform a conventional autorotation landing, therefore it is the bad”. You know what we know so far at the minimum? It crash landed well enough for, at the minimum, most of its crew to survive. Do we even know if it was a double engine failure, the only situation in which autorotation landings are even relevant? We do not.
In any case, you don’t have to go looking very far to find instances of boring old conventional helicopters crashing and killing everyone on board. There’s been a bit of drama in the North Sea oil fields because a number of the Super Puma helicopters the drilling companies use to ferry crews to and from the stations have been going down, often with great loss of life. The capability of Super Pumas to perform a conventional autorotation has been little comfort to the friends and family of those that have been lost. Lately one or two Russian Mi-8 helicopters have gone down with great loss of life, and while I haven’t really looked into the details of the incidents I can assure you that they too are not tilt-rotor aircraft lacking conventional autorotation capability. Yet they still crashed hard.
And speaking of secret military operations, remember the raid that killed Bin Laden? Remember how it embarrassingly revealed the existence of some kind of low observable helicopter because at least one crashed and had to be partially destroyed on site? Another tilt rotor to blame? I mean perhaps we don’t know for sure, but I haven’t seen anyone suggesting it, the best guesses that I’d seen suggested that it was possibly a modified Blackhawk, or something similar with a low observable design.
As a matter of fact, I accidentally ran into a statistic saying that more than 420 American military helicopters have crashed since 2001 while I was trying to look up details of the Osprey’s performance envelope. Helicopters are complicated, difficult to fly aircraft. They fail, they get out of control, and they crash.
@17 cvoinescu
Which is why we want the French approach? The TGV seems to work. :)
Note I’ve only been on a TGV once, IIRC, but I survived despite wandering in to a bar car filled with French rugby players. It took forever to figure out the technical terms they used.
The V-22 is a good idea, but very difficult to implement. Given its (airplane mode) flight characteristics, I wonder (and wondered way back when I first saw the design) why the DoD or designing agency didn’t add additional wing area outboard of the rotors. It could have been made to tilt with the rotors, or not, and still do its intended job most of the time.
There are other helos that have been in service for a very long time that operate on the principle of having two ‘main’ rotors (CH-46, and CH-47) and they would have the same problem in the event of a single rotor failure. I also thought that one of the big issues that delayed the V-22 was interlinking the two engines with a single redundant driveshaft (which if the best design if you really want to be as safe as possible).
I’m going to have to do some research and see what I can find about the actual system as it was finally implemented.
Bell is working on a civilian version of a tilt rotor also, which may be interesting to delve in to.
Nomad@#18:
Apologies that your comment got stuck in a spam filter! I’ve fixed that, now.
A few things:
“what if one engine fails on take-off or landing?”. The only thing that smug question does is expose your ignorance. Ignorance that you really, REALLY should have fixed before writing this article. Google makes it too easy, the only reason not to do the work is if you don’t want to know the answers. You want to know what it does? It continues under the power of its remaining engine, transmitted through a power shaft to the other side. Let me say that again with emphasis, BOTH ROTORS CONTINUE TO RECEIVE POWER.
Ok, thanks for that. You are correct that I did not know there’s a drive-shaft. How interesting!
When I was researching this piece, I reviewed a list of Osprey crashes and they included several incidents where the rotor on one side or the other was stalled, compromised, or failed and the aircraft flipped over and crashed. That was what had stuck in my mind and that’s a legitimate concern.
With respect to Spinney’s credibility – yeah, I’m pretty sure Spinney is biassed against a variety of programs that he sees as wasteful and stupid. He (along with Pierre Sprey) is one of the sources I read regarding procurement shenanigans. As far as his comment about glide ratios: the space shuttle wasn’t much of an airplane, either.
The real point is that since the thing keeps suffering damage from “hard landings” and passengers keep getting injured by them – maybe there’s something wrong with the basic design.
In any case, you don’t have to go looking very far to find instances of boring old conventional helicopters crashing and killing everyone on board.
That’s a false equivalence: boring old conventional helicopters certainly have their share of problems, but they don’t cost as much either.
There’s certainly an argument that can be made that the Osprey is just overcoming “teething pains” and will eventually be a great aircraft. Like the A-10, which had its share of problems, too.